At present there are numerous small devices, generally without an internal power supply, which make use of electronic memories which can be read or read and written by an adequate reading system and which apply to applications requiring a particular security. Reference can e.g. be made to all chip cards, which are used as means for obtaining money (credit cards, bank cards, etc.)., prepayment cards (telephone, coffee machines, car parks, etc.), as well as electronic key systems of varying degrees of sophistication.
However, two important points are detrimental to the reliability of most of these devices and consequently limit their applications. Firstly they are installed on plastics supports, which can be easily deformed or destroyed, even with a relatively limited mechanical or thermal stressing. Secondly the access to the memory requires several electric contacts, which are a significant and endemic source of poor operation. Frequently the situation is that the device (card, key, etc.) can no longer be introduced into the reading device or can no longer be read by the latter.
Therefore the use of such devices is limited to applications where their possible destruction would not have particularly harmful consequences.